Will have ideas but we are not always sure if they're worth pursuing. But what if your idea was brilliant and someone else did it before you? How would you feel if the person who had stolen your idea became a millionaire?
It's happened in the past and it keeps happening to people who don't follow up on their ideas. Because it's not enough just to have something in mind, it's the action that makes it happen or not.
Business ideas is designed especially for that: to allow people to follow through their ideas and make sure they created a sound business out of it.